Field of the Invention
The present invention relates to imaging apparatuses, such as single-lens reflex cameras, and methods of controlling the imaging apparatuses.
Description of the Related Art
Some imaging apparatuses, such as single-lens reflex cameras, are equipped with a focus detection system for detecting the focus condition of a photographing lens through a phase difference detection method and an object detection system for detecting an object, such as a person, present within a field on the basis of light diffused by a focus detection plate. Such focus detection system and object detection system are constituted by a secondary imaging optical system for forming a secondary image of object light that has been transmitted through the photographing lens and has had a primary image formed thereby and an image sensor for outputting a signal of an object image that is a secondary image formed by the secondary imaging optical system. The focus detection system or the object detection system detects the focus condition or detects the object with the use of an image generated on the basis of an output signal of the image sensor.
However, due to the size or cost constraint of the imaging apparatus, the secondary imaging optical system is constituted by a small number of lenses and often has aberration, such as on-axis chromatic aberration. In addition, the imaging performance of the secondary imaging optical system may deteriorate due to various factors including a manufacturing error of the imaging apparatus, a change over time, a change in temperature, and a change in humidity. Accordingly, the resolution of an image used in the focus detection system or the object detection system may deteriorate, leading to a problem in that the detection accuracy of these systems decreases.
With respect to such a problem, Japanese Patent Laid-Open No. 2012-34130, for example, discloses the following configuration that is directed to suppressing a deterioration in the image quality that could be caused by a change in the temperature of an optical system. Specifically, a change in the imaging performance of the optical system that could be caused by a change in the temperature is converted to weights Wr, Wg, and Wb corresponding to respective primary color signals of R, G, and B, and the weights Wr, Wg, and Wb are stored in advance in an image processing unit. The weights Wr, Wg, and Wb are set as appropriate in response to an output of a temperature measuring element, and aberration is thus corrected.
However, the conventional technique disclosed in Japanese Patent Laid-Open No. 2012-34130 targets only a change in the imaging performance of the optical system associated with a change in the temperature.
What causes the imaging performance of the optical system to change includes, in addition to a change in the temperature, a change in the dimensions of a photometric lens or of a member for holding the photometric lens that could be caused by factors including a manufacturing error, a change in humidity, a change over time, or the like. Accordingly, the conventional technique disclosed in Japanese Patent Laid-Open No. 2012-34130 faces an issue that a deterioration in an image caused by a factor other than a change in the temperature cannot be suppressed.